One-Bag 8-Step Ferric Carboxymaltose Desensitization Protocol for Patients with a History of Hypersensitivity Reactions to Iron Preparations

<b><i>Introduction:</i></b> Iron deficiency is the most common cause of anemia in both sexes, although it is more common in women. Intravenous (IV) iron replacement is preferred in patients who cannot tolerate oral treatment or when iron stores need to be replenished rapidly. In this study, we wanted to share the ferric carboxymaltose (FCM) desensitization protocol that we self-created and successfully applied. <b><i>Methods:</i></b> This retrospective cross-sectional study included patients with a history of hypersensitivity reactions (HSRs) to IV or oral iron replacement and patients who were planned to receive IV iron replacement but were referred to the allergy clinic because of have risk factors (atopic diseases, history of HSR to other drugs, high serum tryptase levels, etc.) for HSRs. Before desensitization, some of the patients underwent skin tests (skin prick test and intradermal test) with FCM, and the results were recorded. Skin tests were not performed in patients with a history of drug use (antihistamine, systemic steroid, omalizumab, etc.) that affected the results of skin tests. All patients underwent a one-bag 8-step desensitization protocol with 500 mg FCM and were observed for 2 h after desensitization. <b><i>Results:</i></b> A total of 15 patients (14 females and 1 male) with a mean age of 41.13 ± 11.18 years were included in the study. When the patients were evaluated in terms of the risk of allergic reactions according to their clinical history, 8 patients had a history of anaphylaxis with iron preparations (FCM, <i>n</i> = 4; ferric hydroxide sucrose, <i>n</i> = 2; iron [II] glycine sulfate, <i>n</i> = 1; and iron [III] hydroxide polymaltose, <i>n</i> = 1), and 7 patients had a history of HSR other than anaphylaxis with iron preparations (urticaria, <i>n</i> = 6 [FCM, <i>n</i> = 2; iron (II) glycine sulfate, <i>n</i> = 2; and iron (III) hydroxide polymaltose, <i>n</i> = 2] and urticaria + angioedema [ferric hydroxide sucrose, <i>n</i> = 1]). Desensitization was successfully completed in all patients. No HSR was observed during or after the procedure in any of the patients. <b><i>Conclusion:</i></b> IV iron replacement is a very effective method, especially in cases where iron stores need to be replenished more rapidly. In patients with a history of iron HSR or at risk of developing HSR, replacement can be safely performed without an allergic reaction with successful desensitization protocols.